Nidhiki was once a Toa of Air of the Toa Mangai. He later betrayed his teammates and became a Dark Hunter, and was mutated into an insectoid monster by Roodaka. He was later killed and absorbed by Teridax. He and Krekka were the main antagonists of most of the 2004 storyline.

It is unknown how Nidhiki became a Toa. When the Kanohi Dragon came to Metru Nui, Nidhiki and ten other Toa, led by Lhikan, were summoned to the city to defeat it. After weeks of exhausting combat, they succeeded. While the other Toa were trying to decide what to do with the dragon, Nidhiki attempted to kill it, but was unable to pierce its tough hide. The dragon was then shipped to Xia, whose inhabitants had agreed to keep it out of trouble. (Toa form to the right)

Some time later, while fighting off a group of Dark Hunters attempting to infiltrate Metru Nui, Lhikan and Nidhiki discovered that one of their teammates, Toa Tuyet, was hiding a powerful artifact called the Nui Stone. Worse, in order to get the other Toa to defeat the Dark Hunters, who were after the stone, she was killing Matoran and making it look like the Hunters did it. Upon finding this out, Lhikan and Nidhiki confronted Tuyet and, even though she used the power of the Nui Stone, were able to defeat her. Nidhiki wanted to keep the stone, but to his dismay, Lhikan pulverized it.

One thousand years later, the Dark Hunters, angry at TuragaDume's refusal to allow them to build a base in Metru Nui, invaded. At first, the Toa, vastly outnumbered, were unable to do much. Eventually, they managed to get word to other islands nearby, and were joined by nearly a hundred more Toa. The battle reached a stalemate, until one night, Nidhiki was confronted by the Dark Hunter named Lariska, who, instead of killing Nidhiki, offered him a deal. Nidhiki agreed to betray his fellow Toa and lead them into an ambush in the Canyon of Unending Whispers. However, Lhikan overheard this conversation by following him when he told him about some supplies (those supplies were new toa) and that he needed to get them, but Nidhiki left without asking where to get them and made plans of his own. However, he too was then confronted by Hakann, who offered a new deal: the Toa could spring their trap, but the Dark Hunters would then be allowed to leave the city unharmed. The Toa forces emerged as victors, and Lhikan instructed the Dark Hunters to leave Metru Nui and never come back, and to take Nidhiki with them, which they did.

"Toa... so dramatic. This time, your farewell will be forever, brother."

—Nidhiki to Lhikan

Nidhiki after being mutated

With nowhere else to go, Nidhiki joined the Dark Hunters as an instructor, teaching others – including Vezok – from his experience as a Toa. Wanting to be more than a teacher, he asked to be sent on missions. He got his wish, but to his displeasure was paired with a dim, brutish Dark Hunter named Krekka. From the perspective of the Hunters' leader, "The Shadowed One", this was a good partnership: Krekka could be effective if he stuck to Nidhiki's plans, and, with his loyalty and mindless obedience, could keep Nidhiki in line and make sure he did as he was told.

However, Nidhiki continued to want more, dreaming of being a hero again. When Roodaka came to the Dark Hunters seeking training, he offered to reward her if she would help him escape the island. Instead, she alerted the Shadowed One to Nidhiki's plans and "purchased" her training by mutating him into an insectoid monster, ensuring that he could never be accepted anywhere except the Dark Hunters. Nidhiki - who was entomophobic (having the fear of insectoids) - had been reluctant about this, but had no choice.

Hundreds of years later, Nidhiki and Krekka were sent back to Metru Nui on a mission for MakutaTeridax. Their task was to retrieve six Great Kanoka Disks and to get Toa Lhikan out of the way - an assignment Nidhiki enjoyed, as he still held a grudge over his banishment. While the two were able to capture Lhikan, he had already chosen Matoran replacements and set them on the path to become Toa Metru. Nidhiki blackmailed a Po-Matoran, Ahkmou, into helping him get the Great Disks, but this failed as the Toa Metru were able to get to them first. Nidhiki and Krekka continued to hunt the Toa Metru, almost even getting trampled by a Kikanalo stampede, until Teridax decided to face the Toa himself. In order to increase his power quickly he absorbed the two Dark Hunters and his pet, Nivawk, into his body, killing all three by destroying their minds and absorbing their energy.

Because he died in this fashion, Nidhiki couldn't be revived on the Red Star.

In an alternate Universe visited by Takanuva, Nidhiki and Lhikan confronted Tuyet about the Nui Stone. Nidhiki then joined Tuyet, killed Lhikan and began to brainwash other Toa, making them believe the only way to rule was to control.

As a Toa of Air he controlled the element of air. He carried an Air Scythe and wore the KanohiVolitak, which allowed him to sneak around by muting common noises and making himself semi-invisible. He lost the ability to use these powers after his mutation.

After being mutated, Nidhiki had a pair of pincer claws, and he could fire Kanoka disks and blasts of energy from his mouth. He also had the ability to fly by folding his insectoid body like the way beetles fly.

His head was shaped like a Vahki head, along with a Kanoka Launcher as his mouth. He also had four legs which could be folded to make Nidhiki's flying mode. He had two pincers, which could be opened and closed.